1. Field of the Invention
This invention relates to a reactor suitable for carrying out exothermic reactions in either the gaseous or the vapor phase. More particularly, the invention deals with a reactor having internal cooling pipes.
2. Description of the Prior Art
Reaction vessels having internal cooling tubes are known, for example, from U.S. Pat. No. 2,664,346. These reactors serve the same function as shell and tube heat exchangers, i.e., the removal of heat (e.g. the exchanger of U.S. Pat. No. 4,060,127), plus serving as the reaction vessel. However, larger reactors are required than in the past, not only because all chemical processes are carried out on a larger scale but also because certain processes are being increasingly used, in particular the synthesis of hydrocarbons. One such process for the preparation of hydrocarbons is the conversion of carbon monoxide and hydrogen prepared by the gasification of coal.
It has been found that it is not feasible just to scale up the past reactors, such as the reactor of U.S. Pat. No. 2,664,346, to increase the capacity, as the reactor then becomes less suitable for the purpose envisaged for the following reasons. In the first place the wall strength poses a problem in the case of larger diameters since the wall thickness must be increased and the construction becomes increasingly heavier. In the second place it is desired to have as few as possible penetrations in the shell in view of the high pressures which occur. In the reactor of U.S. Pat. No. 2,664,346 one pipe from each header space and from each manifold space passes through the shell. In addition, as a result of the larger dimensions, the thermal expansion and in particular the stress due to unequal expansion may pose a problem. Finally it becomes difficult, when using larger diameters, to achieve uniform distribution of the gaseous reaction media over the full diameter of the reactor, in particular if--as in the U.S. Pat. No. 2,664,346 reactor--the reaction media enter the reactor centrally at the bottom. In order to make full use of the entire catalyst mass and of the complete cooling surface available, uniform distribution is required. Besides, it is impossible in the U.S. Pat. No. 2,664,346 reactor to negotiate internal access to the cooling tubes for maintenance or inspection without completely dismantling it.